1. Field of the Invention
The present invention relates to a case for containing disk type recording medium, in particular, an optical disk, an optical magnetic disk or the like which is employed in an information recording apparatus such as a data filing apparatus and an image filing apparatus, etc.
2. Description of the Related Art
When the disk type recording medium such as the magnetic disk, optical disk, or optical magnetic disk is loaded into an information recording apparatus, such as a player for playing back information recorded in the disk or a recorder for writing information on the disk, the disk type recording medium has been conventionally loaded manually or loaded together with an exclusive case.
In case where the disk type recording medium is manually loaded into the information recording apparatus, a surface of the disk type recording medium is likely to be damaged with dusts, scratches, fingerprints, etc. These dusts, scratches or fingerprints will sometimes deteriorate reliability of the disk type recording medium in the event of recording and reproducing the information, particularly in recording the information, and as a result, a desired information may not be recorded. In case of recording information especially in the disk type recording medium having a high recording density such as a digital versatile disk (hereinafter referred to as DVD), there has been a fear that a desired information may not be accurately recorded.
Under such situation, in order to prevent adhesion of dusts and the like on a surface of the disk type recording medium, there have been employed such cartridges 201, 301 as shown in FIGS. 5 and 6 which enable the disk type recording medium to be loaded into the information recording apparatus as they are encased in the cartridge.
A conventional cartridge 201 illustrated in FIG. 5 comprises a cartridge body 203 of a synthetic resin or the like which contains the disk type recording medium such as a compact disk (hereinafter referred to as CD) or DVD, and a lid body 204 of a synthetic resin or the like. The cartridge body 203 is formed in a shape of a box which can contain the disk type recording medium and includes a cavity 207 for taking in and out the disk type recording medium, and an opening 205 into which a recording and reproducing head and a rotary table of the information recording apparatus are adapted to be inserted.
A shutter 206 for opening and closing the opening 205 is slidably attached to the cartridge body 203. The shutter 206 is formed of a leaf metal or the like, and biased by a spring (not shown) in a direction of closing the opening 205.
The lid body 204 is formed in a shape of a plate having such a size that it can cover the cavity 207. One end of the lid body 204 is rotatably fixed to one end of the cartridge body 203, while the other end of the lid body 204 is provided with a locking piece 209 which can be locked with the other end of the cartridge body 203. In this manner the lid body 204 is fixed to the cartridge body 203 so that the cavity 207 can be opened and closed.
At the center of the lid body 204, is attached a clamp 210 provided with magnetic plates 211. The clamp 210 is inserted from outside into a circular opening 212 which is formed at the center of the lid body 204. Around the circular opening 212 is formed a flange 208 for preventing the clamp 210 from dropping into the lid body 204, that is, into the cartridge body 203.
The clamp 210 is inserted into the opening 212 from the outside of the lid body 204, and then, fixed to the lid body 204 by fitting a retaining plate 213 for covering the opening 212 to an outer face of the lid body 204.
The clamp 210 thus interposed between the flange 208 and the retaining plate 213 is fitted to the lid body 204 with a backlash so that it may minutely move in a direction of departing from the disk type recording medium contained in the cartridge body 203 and along a surface of the disk type recording medium.
When the cartridge 201 of the structure as described above and illustrated in FIG. 5 is loaded into the information recording apparatus with the disk type recording medium contained therein, the shutter 206 slidingly moves against a tension of the spring to open the opening 205. Then, the rotary table of the information recording apparatus enters into the cartridge body 203 through the opening 205.
On this occasion, a magnet fixed on the rotary table attracts the magnetic plates 211 of the clamp 210, and the disk type recording medium is centered and mounted on the rotary table. In a state where the disk type recording medium is centered and mounted, the clamp 210 is held at such a position that it may neither contact with the flange 208 nor the retaining plate 213. As the rotary table rotates, the disk type recording medium and the clamp 210 will rotate with the rotation of the rotary table to perform recording and reproduction of the desired information.
The cartridge 301 of the second conventional example illustrated in FIG. 6 comprises a cartridge body 303 of a synthetic resin or the like which contains the disk type recording medium such as the CD or DVD, and a lid body 304 of a synthetic resin or the like. The body 303 is formed in a shape of a box which can contain the disk type recording medium and includes a cavity 307 for taking in and out the disk type recording medium, and an opening 305 into which a recording and playback head and the rotary table of the information recording apparatus are adapted to be inserted. Further, the lid body 303 is provided with locking holes 303b which serve as locking retainers, at its peripheral wall 303a positioned at one end thereof.
The lid body 304 is formed in a shape of a plate having such a size that it can cover the cavity 307. One end of the lid body 304 is provided with locking projections 306a which are adapted to engage with the locking holes 303b, while the other end of the lid body 304 is provided with a locking piece 306b which can be locked with a peripheral wall 303c facing with the peripheral wall 303a of the body 303. In this manner the lid body 304 is fixed to the cartridge body 303 by an engagement of the locking projections 306a with the locking holes 303b and an engagement of the locking piece 306b with the peripheral wall 303c, so that the cavity 307 can be opened and closed.
At the center of the lid body 304, is attached a clamp 310 provided with magnetic plates 311. The clamp 310 is inserted from outside into a circular opening 312 which is formed at the center of the lid body 304. Around the circular opening 312 is formed a flange 308 for preventing the clamp 310 from dropping into the lid body 304, that is, into the cartridge body 303.
The clamp 310 is inserted into the opening 312 from the outside of the lid body 304, and then, fixed to the lid body 304 by fitting a retaining plate 313 for covering the opening 312 to an outer face of the lid body 304.
The clamp 310 thus interposed between the flange 308 and the retaining plate 313 is fitted to the lid body 304 with a backlash so that it may minutely move in a direction of departing from the disk type recording medium contained in the cartridge body 303 and along a surface of the disk type recording medium.
When the cartridge 301 is carried or stored with the disk type recording medium contained therein, the cartridge 301 is encased in a protective case 314 in order to prevent dusts from entering through the opening 305 and adhering to the surface of the disk type recording medium.
The protective case 314 is formed of a synthetic resin or the like, and consists of a flat bottom wall 315, a pair of side walls 316, 316 provided in an upright form from opposite edges of the bottom wall 315, and a rear wall 317 provided in an upright form from a rear edge of the bottom wall 315 connected to the side walls 316, 316, all of which are integrally formed.
The bottom wall 315 has a dimension larger than the cartridge 301 in width. The side walls 316, 316 have a height larger than a thickness of the cartridge 301. The side walls 316, 316 are respectively formed with inwardly projecting guide ridges 318, 318 in a longitudinal direction thereof. The side walls 316, 316 are further provided with cartridge retaining projections (not shown) adjacent to the rear wall 317 for detachably locking the cartridge 301.
With the above described structure, the protective case 314 contains the cartridge 301 in a state where the cartridge 301 is interposed between the bottom plate 315 and the ridges 318 with its opening 305 faced with the bottom wall 315. When the cartridge 301 is encased in the protective case 314, the cartridge 301 is guided along the side walls 316, 316 by the aid of the guide ridges 318, 318 to be abutted against the rear wall 317.
On this occasion, the cartridge retaining projections lock the cartridge 301 and prevent the cartridge 301 from unintentionally dropping. In this manner, the protective case 314 covers the opening 305 to prevent an intrusion of dusts and the like into the cartridge 301.
The cartridge 301 of the structure as described above and illustrated in FIG. 6 is removed from the protective case 314 and loaded into the information recording apparatus with the disk type recording medium contained therein. Then, the rotary table of the information recording apparatus enters into the cartridge 301 through the opening 305.
On this occasion, the magnet fixed on the rotary table attracts the magnetic plates 311 of the clamp 310, and the disk type recording medium is centered and mounted on the rotary table. In a state where the disk type recording medium is centered and mounted, the clamp 310 is held at such a position that it may neither contact with the flange 308 nor the retaining plate 313. When the rotary table rotates, the disk type recording medium and the clamp 310 will rotate with the rotation of the rotary table to perform recording and reproduction of the desired information.
However, in both the conventional cartridges 201, 301 illustrated in FIGS. 5 and 6, the lid bodies 204, 304 are provided with the clamps 210, 310 for centering the disk type recording medium. For this reason, the number of the components has been apt to increase.
Moreover, the number of assembling steps for fitting the clamps 210, 310 to the lid bodies 204, 304, for example, a step of forming the flanges 208, 308 around the openings 212, 312 of the lid bodies 204, 304, or a step of inserting the clamps 210, 310 into the openings 212, 312 and a step of attaching the retaining plates 213, 313, has been apt to increase. Therefore, there has been a tendency that a unit price of the conventional cartridges 210, 301 increases.
Further, in the conventional cartridges 201, 301, the clamps 210, 310 are attached to the lid bodies 204, 304 with the backlashes as described above. The disk type recording medium is centered by means of the clamps 210, 310 when the magnetic plates 211, 311 are attracted by the magnet on the rotary table.
For this reason, when the disk type recording medium having relatively high recording density such as the DVD is recorded and played back, it has been difficult to secure the required centering accuracy. The disk type recording medium is likely to get eccentric during the rotation, and it has been difficult to record the desired information in the disk type recording medium and to reproduce the recorded information with accuracy.
Furthermore, in the cartridge 201 illustrated in FIG. 5, the shutter 206 which is a separate member from the cartridge body 203 and the lid body 204 formed of the synthetic resin is slidably attached to the cartridge body 203. This shutter 206 is formed of the leaf metal or the like but not of the synthetic resin. The dimensional accuracy of this shutter 206 is maintained at relatively high grade in order to realize a smooth sliding movement of the shutter.
As described, because the conventional cartridge 201 is provided with the shutter 206 which is a separate body from the body 203 and the lid body 204 and formed of a different material, the number of the components has been increased. Further, because the shutter 206 is formed of the leaf metal or the like with relatively high dimensional accuracy, the manufacturing steps of the shutter 206 as well as the assembling steps in assembling the shutter 206 to the body 203 have been apt to increase. Accordingly, the unit price of the cartridge 201 as illustrated in FIG. 5 has been apt to increase the more.
In view of the above, an object of the invention is to provide a case for containing a disk type recording medium at a low cost which can protect the recording medium contained therein from dusts and the like enabling the recording and playback of this disk type recording medium to be reliably performed.